1 Technical Field
The present invention relates generally to stators for rotating electric machines that are used in, for example, motor vehicles as electric motors and electric generators, and more particularly to winding structures of the stators.
2 Description of Related Art
There is known, for example from Japanese Patent No. 3707606, a method of manufacturing a stator for a rotating electric machine.
Specifically, according to the method, as shown in FIG. 19, the stator is manufactured by: (1) mounting a plurality of winding groups 103, each of which belongs to one of U, V and W phases, onto teeth 102 formed in a flat band-shaped stator core 101; (2) bending the flat band-shaped stator core 101 into an annular shape so as to make each of the teeth 6 extend radially inward; and (3) joining opposite ends of the bent stator core 101 together.
However, with the above method, it is necessary to divide one of the winding groups 103 into two segments 104 at the opposite ends (i.e., the front and rear ends in FIG. 19) of the flat band-shaped stator core 101. Consequently, after bending the flat band-shaped stator core 101 into the annular shape, it is further necessary to join the two segments 104 to restore the divided winding group 103. As a result, the manufacturing process of the stator is complicated, thereby lowering the productivity of the stator.
In addition, in the example illustrated in FIG. 19, the number of the teeth 102 formed in the stator core 101 is equal to 48; the number of phases is equal to 3; the number of poles (i.e., the number of magnetic poles formed in a rotor of the rotating electric machine) is equal to 16. Each of the winding groups 103 is concentratedly wound at full pitch on the teeth 102 of the stator core 101. In other words, each of the winding groups 103 is a full-pitch concentrated winding group. However, even if the winding groups 103 were distributedly wound at full pitch on the teeth 102 of the stator core 101, the manufacturing process of the stator would still be complicated by the necessity of joining the two segments 104 of the divided winding group 103.